Planetary transmissions having three interconnected gear sets and clutched input

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission family members include three planetary gear sets having seven torque-transmitting mechanisms and three fixed interconnecting members. The powertrain includes an engine that is selectively connectable to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members and the transmission housing, and are operated in combinations of three to establish at least eight forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingthree planetary gear sets that are controlled by seventorque-transmitting devices to provide at least eight forward speedratios and at least one reverse speed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

It has been suggested that the number of forward speed ratios beincreased to six or more. Six-speed transmissions are disclosed in U.S.Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; and U.S. Pat. No.6,422,969 issued to Raghavan and Usoro on Jul. 23, 2002.

Six-speed transmissions offer several advantages over four- andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five or six-speed devices due to the size and complexityof these transmissions.

Seven-speed transmissions are disclosed in U.S. Pat. No. 6,623,397issued to Raghavan, Bucknor and Usoro. Eight speed transmissions aredisclosed in U.S. Pat. No. 6,425,841 issued to Haka. The Hakatransmission utilizes three planetary gear sets and six torquetransmitting devices, including two brakes and two clutches, to provideeight forward speed ratios and a reverse speed ratio. One of theplanetary gear sets is positioned and operated to establish two fixedspeed input members for the remaining two planetary gear sets. The Hakatransmission requires two double-transition shifts. Seven-, eight- andnine-speed transmissions provide further improvements in accelerationand fuel economy over six-speed transmissions. However, like thesix-speed transmissions discussed above, the development of seven-,eight- and nine-speed transmissions has been precluded because ofcomplexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved familyof transmissions having three planetary gear sets controlled to provideat least eight forward speed ratios and at least one reverse speedratio.

In one aspect of the present invention, the family of transmissions hasthree planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, a ring gear, or aplanet carrier assembly member.

In referring to the first, second and third gear sets in thisdescription and in the claims, these sets may be counted “first” to“third” in any order in the drawings (i.e., left to right, right toleft, etc.).

In another aspect of the present invention, the planetary gear sets maybe of the single pinion-type or of the double pinion-type.

In yet another aspect of the present invention, a first member of thefirst planetary gear set is continuously interconnected with a firstmember of the second planetary gear set through a first interconnectingmember.

In a further aspect of the present invention, a second member of thefirst planetary gear set is continuously connected with a second memberof the second planetary gear set through a second interconnectingmember.

In another aspect of the present invention, a third member of the secondplanetary gear set is continuously connected with a first member of thethird planetary gear set through a third interconnecting member.

In yet a further aspect of the invention, each family memberincorporates an output shaft which is continuously connected with amember of the planetary gear sets, and an input shaft which is notcontinuously connected with any member of the planetary gear sets but isselectively connectable with at least one member of the planetary gearsets through at least one of seven torque-transmitting mechanisms.

In still a further aspect of the invention, a first torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with the input shaft.

In another aspect of the invention, a second torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst, second or third planetary gear set with the input shaft.

In a still further aspect of the invention, a third torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst or third planetary gear set with the input shaft or with anothermember of the first or third planetary gear set.

In a still further aspect of the invention, a fourth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst or third planetary gear set with another member of the first,second or third planetary gear set.

In a still further aspect of the invention, a fifth torque-transmittingmechanism, such as a brake, selectively connects a member of the firstor third planetary gear set with a stationary member (transmissioncase).

In still another aspect of the invention, a sixth torque-transmittingmechanism, such as a brake, selectively connects a member of the secondor third planetary gear set with the stationary member (transmissioncase).

In still another aspect of the invention, a seventh torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thesecond or third planetary gear set with another member of the first,second or third planetary gear set. Alternatively, the seventhtorque-transmitting mechanism, such as a brake, selectively connects amember of the second or third planetary gear set with the stationarymember (transmission case).

In still another aspect of the invention, the seven torque-transmittingmechanisms are selectively engageable in combinations of three to yieldat least eight forward speed ratios and at least one reverse speedratio.

The above objects and other objects, features, and advantages of thepresent invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1 a;

FIG. 2 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 2 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2 a;

FIG. 3 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 3 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3 a;

FIG. 4 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 4 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4 a;

FIG. 5 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 5 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5 a;

FIG. 6 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 6 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6 a;

FIG. 7 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 7 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7 a;

FIG. 8 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 8 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8 a;

FIG. 9 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 9 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9 a;

FIG. 10 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 10 a;

FIG. 11 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 11 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11 a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1 a a powertrain 10 having a conventional engine 12, a planetarytransmission 14, and a conventional final drive mechanism 16.

The planetary transmission 14 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 18, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 18 includes three planetary gear sets20, 30 and 40.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly 26. The planet carrier assembly26 includes a plurality of pinion gears 27 rotatably mounted on acarrier member 29 and disposed in meshing relationship with both the sungear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear arrangement also includes seven torque-transmittingmechanisms 50, 52, 54, 56, 57, 58 and 59. The torque-transmittingmechanisms 50, 52, 54, 56 and 57 are rotating-type torque-transmittingmechanisms, commonly termed clutches. The torque-transmitting mechanisms58 and 59 are stationary-type torque transmitting mechanisms, commonlytermed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 44. The planet carrier assembly member 26 is continuouslyconnected with the ring gear member 34 through the interconnectingmember 70. The sun gear member 22 is continuously connected with the sungear member 32 through the interconnecting member 72. The planet carrierassembly member 36 is continuously connected with the sun gear member 42through the interconnecting member 74.

The clutch 50 selectively connects the sun gear member 22 with the inputshaft 17. The clutch 52 selectively connects the planet carrier assemblymember 36 with the input shaft 17. The clutch 54 selectively connectsthe planet carrier assembly member 46 with the input shaft 17. Theclutch 56 selectively connects the ring gear member 34 with the planetcarrier assembly member 46. The clutch 57 selectively connects the ringgear member 34 with the ring gear member 44. The brake 58 selectivelyconnects the planet carrier assembly member 26 with the transmissionhousing 60. The brake 59 selectively connects the ring gear member 24with the transmission housing 60.

As shown in FIG. 1 b, and in particular the truth table disclosedtherein, the torque-transmitting mechanisms are selectively engaged incombinations of three to provide eight forward speed ratios (includingextra second and third speed ratios: 2′ and 3′) and two reverse speedratios.

The reverse speed ratio is established with the engagement of theclutches 50, 56 and the brake 58. The clutch 50 connects the sun gearmember 22 with the input shaft 17. The clutch 56 connects the ring gearmember 34 with the planet carrier assembly member 46. The brake 58connects the planet carrier assembly member 26 with the transmissionhousing 60. The sun gear members 22 and 32 rotate at the same speed asthe input shaft 17. The planet carrier assembly members 26 and 46 andthe ring gear member 34 do not rotate. The planet carrier assemblymember 36 rotates at the same speed as the sun gear member 42. Theplanet carrier assembly member 36 rotates at a speed determined from thespeed of the sun gear member 32 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The ring gear member 44 rotates at thesame speed as the output shaft 19. The ring gear member 44, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the sun gear member 42 and the ring gear/sun gear tooth ratioof the planetary gear set 40. The numerical value of the reverse speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 30 and 40.

The reverse #2 speed ratio is established with the engagement of theclutches 52 and 56, and the brake 58. The clutch 52 connects the planetcarrier assembly member 36 with the input shaft 17. The clutch 56connects the ring gear member 34 with the planet carrier assembly member46. The brake 58 connects the planet carrier assembly member 26 with thetransmission housing 60. The sun gear members 22, 32 rotate at the samespeed. The planet carrier assembly member 26, ring gear member 34, andplanet carrier assembly member 46 do not rotate. The planet carrierassembly member 36 and sun gear member 42 rotate at the same speed asthe input shaft 17. The ring gear member 44 rotates at the same speed asthe output shaft 19. The ring gear member 44, and therefore the outputshaft 19, rotates at a speed determined from the sun gear member 42 andthe ring gear/sun gear tooth ratio of the planetary gear set 40.

The first forward speed ratio is established with the engagement of theclutches 50, 56 and the brake 59. The clutch 50 connects the sun gearmember 22 with the input shaft 17. The clutch 56 connects the ring gearmember 34 with the planet carrier assembly member 46. The brake 59connects the ring gear member 24 with the transmission housing 60. Thesun gear members 22, 32 rotate at the same speed as the input shaft 17.The planet carrier assembly member 26 rotates at the same speed as thering gear member 34 and the planet carrier assembly member 46. The ringgear member 24 does not rotate. The planet carrier assembly member 26rotates at a speed determined from the speed of the sun gear member 22and the ring gear/sun gear tooth ratio of the planetary gear set 20. Theplanet carrier assembly member 36 rotates at the same speed as the sungear member 42. The planet carrier assembly member 36 rotates at a speeddetermined from the speed of the ring gear member 34, the speed of thesun gear member 32, and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The ring gear member 44 rotates at the same speedas the output shaft 19. The ring gear member 44, and therefore theoutput shaft 19, rotates at a speed determined from the speed of theplanet carrier assembly member 46, the speed of the sun gear member 42,and the ring gear/sun gear tooth ratio of the planetary gear set 40.

The second forward speed ratio is established with the engagement of theclutches 50, 57 and the brake 59. The clutch 50 connects the sun gearmember 22 with the input shaft 17. The clutch 57 connects the ring gearmember 34 with the ring gear member 44. The brake 59 connects the ringgear member 24 with the transmission housing 60. The sun gear members22, 32 rotate at the same speed as the input shaft 17. The planetcarrier assembly member 26, ring gear member 34, and ring gear member 44rotate at the same speed as the output shaft 19. The ring gear member 24does not rotate. The speed of the planet carrier assembly member 26 isdetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The planetcarrier assembly member 36 rotates at the same speed as the sun gearmember 42. The speed of the ring gear member 34, and therefore theoutput shaft 19, is determined from the speed of the planet carrierassembly member 36, the speed of the sun gear member 32, and the ringgear/sun gear tooth ratio of the planetary gear set 30. The numericalvalue of the second forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20 and 30.

The extra second forward speed ratio (2′) is established with theengagement of the clutches 52, 56 and the brake 59. The clutch 52connects the planet carrier assembly member 36 with the input shaft 17.The clutch 56 connects the ring gear member 34 with the planet carrierassembly member 46. The brake 59 connects the ring gear member 24 withthe transmission housing 60. The sun gear members 22, 32 rotate at thesame speed. The planet carrier assembly member 26 rotates at the samespeed as the ring gear member 34 and the planet carrier assembly member46. The ring gear member 24 does not rotate. The speed of the planetcarrier assembly member 26 is determined from the speed of the sun gearmember 22 and the ring gear/sun gear tooth ratio of the planetary gearset 20. The planet carrier assembly member 36 and sun gear member 42rotate at the same speed as the input shaft 17. The speed of the ringgear member 34 is determined from the speed of the planet carrierassembly member 36, the speed of the sun gear member 32, and the ringgear/sun gear tooth ratio of the planetary gear set 30. The ring gearmember 44 rotates at the same speed as the output shaft 19. The speed ofthe ring gear member 44, and therefore the output shaft 19, isdetermined from the speed of the planet carrier assembly member 46, thespeed of the sun gear member 42, and the ring gear/sun gear tooth ratioof the planetary gear set 40. The numerical value of the extra secondforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 20, 30 and 40.

The third forward speed ratio is established with the engagement of theclutches 52, 57 and the brake 59. The clutch 52 connects the planetcarrier assembly member 36 with the input shaft 17. The clutch 57connects the ring gear member 34 with the ring gear member 44. The brake59 connects the ring gear member 24 with the transmission housing 60.The sun gear member 22 rotates at the same speed as the sun gear member32. The planet carrier assembly member 26 and ring gear members 34, 44rotate at the same speed as the output shaft 19. The ring gear member 24does not rotate. The sun gear member 22 rotates at a speed determinedfrom the speed of the planet carrier assembly member 26 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The planetcarrier assembly member 36 and sun gear member 42 rotate at the samespeed as the input shaft 17. The speed of the ring gear member 34, andtherefore the output shaft 19, is determined from the speed of theplanet carrier assembly member 36, the speed of the sun gear member 32,and the ring gear/sun gear tooth ratio of the planetary gear set 30. Thenumerical value of the third forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 20 and30.

The extra third forward speed ratio (3′) is established with theengagement of the clutches 54, 56 and the brake 59. The clutch 54connects the planet carrier assembly member 46 with the input shaft 17.The clutch 56 connects the ring gear member 34 with the planet carrierassembly member 46. The brake 59 connects the ring gear member 24 withthe transmission housing 60. The sun gear member 22 rotates at the samespeed as the sun gear member 32. The ring gear member 24 does notrotate. The planet carrier assembly member 26, ring gear member 34, andplanet carrier assembly member 46 rotate at the same speed as the inputshaft 17. The speed of the sun gear member 22 is determined from thespeed of the planet carrier assembly member 26 and the ring gear/sungear tooth ratio of the planetary gear set 20. The planet carrierassembly member 36 rotates at the same speed as the sun gear member 42.The speed of the planet carrier assembly member 36 is determined fromthe speed of the ring gear member 34, the speed of the sun gear member32, and the ring gear/sun gear tooth ratio of the planetary gear set 30.The ring gear member 44 rotates at the same speed as the output shaft19. The speed of the ring gear member 44, and therefore the output shaft19, is determined from the speed of the planet carrier assembly member46, the speed of the sun gear member 42, and the ring gear/sun geartooth ratio of the planetary gear set 40. The numerical value of theextra third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30 and 40.

The fourth forward speed ratio is established with the engagement of theclutches 54, 57 and the brake 59. The clutch 54 connects the planetcarrier assembly member 46 with the input shaft 17. The clutch 57connects the ring gear member 34 with the ring gear member 44. The brake59 connects the ring gear member 24 with the transmission housing 60.The sun gear member 22 rotates at the same speed as the sun gear member32. The planet carrier assembly member 26 and ring gear members 34, 44rotate at the same speed as the output shaft 19. The ring gear member 24does not rotate. The speed of the planet carrier assembly member 26 isdetermined from the speed of the sun gear member 22 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The planetcarrier assembly member 36 rotates at the same speed as the sun gearmember 42. The speed of the planet carrier assembly member 36 isdetermined from the speed of the ring gear member 34, the speed of thesun gear member 32, and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The planet carrier assembly member 46 rotates atthe same speed as the input shaft 17. The speed of the ring gear member44, and therefore the output shaft 19, is determined from the speed ofthe planet carrier assembly member 46, the speed of the sun gear member42, and the ring gear/sun gear tooth ratio of the planetary gear set 40.The numerical value of the fourth forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of planetary gear sets 20,30 and 40.

The fifth forward speed ratio is established with the engagement of theclutches 52, 54 and the brake 59. The clutch 52 connects the planetcarrier assembly member 36 with the input shaft 17. The clutch 54connects the planet carrier assembly member 46 with the input shaft 17.The brake 59 connects the ring gear member 24 with the transmissionhousing 60. The sun gear member 22 rotates at the same speed as the sungear member 32. The planet carrier assembly member 26 rotates at thesame speed as the ring gear member 34. The ring gear member 24 does notrotate. The speed of the planet carrier assembly member 26 is determinedfrom the speed of the sun gear member 22 and the ring gear/sun geartooth ratio of the planetary gear set 20. The planet carrier assemblymember 36 and sun gear member 42 rotate at the same speed as the inputshaft 17. The speed of the ring gear member 34 is determined from thespeed of the planet carrier assembly member 36, the speed of the sungear member 32, and the ring gear/sun gear tooth ratio of the planetarygear set 30. The planet carrier assembly member 46 rotates at the samespeed as the input shaft 17. The ring gear member 44 rotates at the samespeed as the output shaft 19. The ring gear member 44, and therefore theoutput shaft 19, rotates at a speed determined from the speed of theplanet carrier assembly member 46, the speed of the sun gear member 42,and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the fifth forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 20, 30and 40.

The sixth forward speed ratio is established with the engagement of theclutches 50, 54 and the brake 59. The clutch 50 connects the sun gearmember 22 with the input shaft 17. The clutch 54 connects the planetcarrier assembly member 46 with the input shaft 17. The brake 59connects the ring gear member 24 with the transmission housing 60. Thesun gear members 22, 32 rotate at the same speed as the input shaft 17.The planet carrier assembly member 26 rotates at the same speed as thering gear member 34. The ring gear member 24 does not rotate. The speedof the planet carrier assembly member 26 is determined from the speed ofthe sun gear member 22 and the ring gear/sun gear tooth ratio of theplanetary gear set 20. The planet carrier assembly member 36 rotates atthe same speed as the sun gear member 42. The speed of the planetcarrier assembly member 36 is determined from the speed of the ring gearmember 34, the speed of the sun gear member 32, and the ring gear/sungear tooth ratio of the planetary gear set 30. The ring gear member 44rotates at the same speed as the output shaft 19. The planet carrierassembly member 46 rotates at the same speed as the input shaft 17. Thespeed of the ring gear member 44, and therefore the output shaft 19, isdetermined from the speed of the planet carrier assembly member 46, thespeed of the sun gear member 42, and the ring gear/sun gear tooth ratioof the planetary gear set 40. The numerical value of the sixth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 20, 30 and 40.

The seventh forward speed ratio is established with the engagement ofthe clutch 50, 54 and the brake 58. The clutch 50 connects the sun gearmember 22 with the input shaft 17. The clutch 54 connects the planetcarrier assembly member 46 with the input shaft 17. The brake 58connects the planet carrier assembly member 26 with the transmissionhousing 60. The sun gear members 22, 32 rotate at the same speed as theinput shaft 17. The planet carrier assembly member 26 and ring gearmember 34 do not rotate. The planet carrier assembly member 36 rotatesat the same speed as the sun gear member 42. The speed of the planetcarrier assembly member 36 is determined from the speed of the sun gearmember 32 and the ring gear/sun gear tooth ratio of the planetary gearset 30. The planet carrier assembly member 46 rotates at the same speedas the input shaft 17. The ring gear member 44 rotates at the same speedas the output shaft 19. The speed of the ring gear member 44, andtherefore the output shaft 19, is determined from the speed of theplanet carrier assembly member 46, the speed of the sun gear member 42,and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the seventh forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets30 and 40.

The eighth forward speed ratio is established with the engagement of theclutch 54 and the brakes 58, 59. The clutch 54 connects the planetcarrier assembly member 46 with the input shaft 17. The brake 58connects the planet carrier assembly member 26 with the transmissionhousing 60. The brake 59 connects the ring gear member 24 with thetransmission housing 60. The planetary gear sets 20, 30 and sun gearmember 42 do not rotate. The planet carrier assembly member 46 rotatesat the same speed as the input shaft 17. The ring gear member 44 rotatesat the same speed as the output shaft 19. The speed of the ring gearmember 44, and therefore the output shaft 19, is determined from thespeed of the planet carrier assembly member 46 and the ring gear/sungear tooth ratio of the planetary gear set 40. The numerical value ofthe eighth forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 40.

As set forth above, the engagement schedule for the torque-transmittingmechanisms is shown in the truth table of FIG. 1 b. This truth tablealso provides an example of speed ratios that are available utilizingthe ring gear/sun gear tooth ratios given by way of example in FIG. 1 b.The N_(R1)/N_(S1) value is the tooth ratio of the planetary gear set 20;the N_(R2)/N_(S2) value is the tooth ratio of the planetary gear set 30;and the N_(R3)/N_(S3) value is the tooth ratio of the planetary gear set40. Also, the chart of FIG. 1 b describes the ratio steps that areattained utilizing the sample of tooth ratios given. For example, thestep ratio between the first and second forward speed ratios is 1.47,while the step ratio between the reverse and first forward ratio is−1.46.

FIG. 2 a shows a powertrain 110 having a conventional engine 12, aplanetary transmission 114, and a conventional final drive mechanism 16.

The planetary transmission 114 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 118, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 118 includes three planetary gearsets 120, 130 and 140.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly 126. The planet carrierassembly 126 includes a plurality of pinion gears 127 rotatably mountedon a carrier member 129 and disposed in meshing relationship with boththe sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear member 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear arrangement 118 also includes seventorque-transmitting mechanisms 150, 152, 154, 156, 157, 158 and 159. Thetorque-transmitting mechanisms 150, 152, 154, 156 and 157 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 158 and 159 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 144. The ring gear member 124 is continuously connected with theplanet carrier assembly member 136 through the interconnecting member170. The sun gear member 122 is continuously connected with the sun gearmember 132 through the interconnecting member 172. The ring gear member134 is continuously connected with the sun gear member 142 through theinterconnecting member 174.

The clutch 150 selectively connects the planet carrier assembly member136 with the input shaft 17. The clutch 152 selectively connects the sungear member 142 with the input shaft 17. The clutch 154 selectivelyconnects the planet carrier assembly member 146 with the input shaft 17.The clutch 156 selectively connects the sun gear member 122 with theplanet carrier assembly member 146. The clutch 157 selectively connectsthe planet carrier assembly member 126 with the planet carrier assemblymember 146. The brake 158 selectively connects the planet carrierassembly member 136 with the transmission housing 160. The brake 159selectively connects the sun gear member 122 with the transmissionhousing 160.

The truth table of FIG. 2 b describes the engagement sequence utilizedto provide eight forward speed ratios and two reverse speed ratios inthe planetary gear arrangement 118 shown in FIG. 2 a.

The truth tables given in FIGS. 2 b, 3 b, 4 b, 5 b, 6 b, 7 b, 8 b, 9 b,10 b and 11 b show the engagement sequences for the torque-transmittingmechanisms to provide at least eight forward speed ratios and at leastone reverse ratio. As shown and described above for the configuration inFIG. 1 a, those skilled in the art will understand from the respectivetruth tables how the speed ratios are established through the planetarygear sets identified in the written description.

As set forth above, the truth table of FIG. 2 b describes the engagementsequence of the torque-transmitting mechanisms utilized to provide tworeverse drive ratios and eight forward speed ratios. The truth tablealso provides an example of the ratios that can be attained with thefamily members shown in FIG. 2 a utilizing the sample tooth ratios givenin FIG. 2 b. The N_(R1)/N_(S1) value is the tooth ratio of the planetarygear set 120; the N_(R2)/N_(S1) value is the tooth ratio of theplanetary gear set 130; and the N_(R3)/N_(S3) value is the tooth ratioof the planetary gear set 140. Also shown in FIG. 2 b are the ratiosteps between single step ratios in the forward direction as well as thereverse to first ratio step ratio. For example, the first to second stepratio is 1.49.

Turning to FIG. 3 a, a powertrain 210 includes the engine 12, aplanetary transmission 214, and a final drive mechanism 16. Theplanetary transmission 214 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 218, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 218 includes three planetary gearsets 220, 230 and 240.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly 226. The planet carrierassembly 226 includes a plurality of pinion gears 227 rotatably mountedon a carrier member 229 and disposed in meshing relationship with boththe sun gear member 222 and the ring gear member 224.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear arrangement 218 also includes seventorque-transmitting mechanisms 250, 252, 254, 256, 257, 258 and 259. Thetorque-transmitting mechanisms 250, 252, 254, 256 and 257 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 258 and 259 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the ring gearmember 244. The ring gear member 244 is continuously connected with thesun gear member 232 through the interconnecting member 270. The sun gearmember 222 is continuously connected with the planet carrier assemblymember 236 through the interconnecting member 272. The ring gear member234 is continuously connected with the sun gear member 242 through theinterconnecting member 274.

The clutch 250 selectively connects the planet carrier assembly member236 with the input shaft 17. The clutch 252 selectively connects the sungear member 242 with the input shaft 17. The clutch 254 selectivelyconnects the planet carrier assembly member 246 with the input shaft 17.The clutch 256 selectively connects the planet carrier assembly member226 with the planet carrier assembly member 246. The clutch 257selectively connects the planet carrier assembly member 226 with thering gear member 244. The brake 258 selectively connects the planetcarrier assembly member 236 with the transmission housing 260. The brake259 selectively connects the ring gear member 224 with the transmissionhousing 260.

As shown in the truth table in FIG. 3 b, the torque-transmittingmechanisms are engaged in combinations of three to establish eightforward speed ratios, and two reverse speed ratios.

As previously set forth, the truth table of FIG. 3 b describes thecombinations of engagements utilized for the forward and reverse speedratios. The truth table also provides an example of speed ratios thatare available with the family member described above. These examples ofspeed ratios are determined utilizing the tooth ratios given in FIG. 3b. The N_(R1)/N_(S1) value is the tooth ratio of the planetary gear set220; the N_(R2)/N_(S2) value is the tooth ratio of the planetary gearset 230; and the N_(R3)/N_(S3) value is the tooth ratio of the planetarygear set 240. Also depicted in FIG. 3 b is a chart representing theratio steps between adjacent forward speed ratios and between the firstand reverse speed ratio. For example, the first to second ratiointerchange has a step of 1.49.

A powertrain 310, shown in FIG. 4 a, includes the engine 12, a planetarytransmission 314, and the final drive mechanism 16. The planetarytransmission 314 includes an input shaft 17 continuously connected withthe engine 12, a planetary gear arrangement 318, and output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 318 includes three planetary gear sets 320, 330 and340.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of pinion gears 327 rotatablymounted on a carrier member 329 and disposed in meshing relationshipwith both the sun gear member 322 and the ring gear member 324.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear arrangement 318 also includes seventorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359. Thetorque-transmitting mechanisms 350, 352, 354, 356 and 357 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 358 and 359 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 326. The planet carrier assembly member 326 iscontinuously connected with the planet carrier assembly member 336through the interconnecting member 370. The sun gear member 322 iscontinuously connected with the ring gear member 334 through theinterconnecting member 372. The sun gear member 332 is continuouslyconnected with the ring gear member 344 through the interconnectingmember 374.

The clutch 350 selectively connects the ring gear member 334 with theinput shaft 17. The clutch 352 selectively connects the ring gear member324 with the input shaft 17. The clutch 354 selectively connects the sungear member 342 with the input shaft 17. The clutch 356 selectivelyconnects the ring gear member 334 with the sun gear member 342. Theclutch 357 selectively connects the planet carrier assembly member 346with the sun gear member 342. The brake 358 selectively connects thering gear member 324 with the transmission housing 360. The brake 359selectively connects the planet carrier assembly member 346 with thetransmission housing 360.

The truth table shown in FIG. 4 b describes the engagement combinationand the engagement sequence necessary to provide the reverse drive ratioand eight forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 4 b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 4 b. The N_(R1)/N_(S1) value is the tooth ratio for the planetarygear set 320; the N_(R2)/N_(S2) value is the tooth ratio for theplanetary gear set 330; and the N_(R3)/N_(S3) value is the tooth ratiofor the planetary gear set 340. Also given in FIG. 4 b is a chartdescribing the step ratios between the adjacent forward speed ratios andthe reverse to first forward speed ratio. For example, the first tosecond forward speed ratio step is 2.17.

A powertrain 410, shown in FIG. 5 a, includes the engine 12, a planetarytransmission 414 and the final drive mechanism 16. The planetarytransmission 414 includes a planetary gear arrangement 418, input shaft17 and output shaft 19. The planetary gear arrangement 418 includesthree simple planetary gear sets 420, 430 and 440.

The planetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly 426. The planet carrierassembly 426 includes a plurality of pinion gears 427 rotatably mountedon a carrier member 429 and disposed in meshing relationship with boththe sun gear member 422 and the ring gear member 424.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the ring gear member 434 and the sun gear member 432.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear arrangement 418 also includes seventorque-transmitting mechanisms 450, 452, 454, 456, 457, 458 and 459. Thetorque-transmitting mechanisms 450, 452, 454, 456 and 457 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 458 and 459 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 426. The planet carrier assembly member 426 iscontinuously connected with the planet carrier assembly member 436through the interconnecting member 470. The sun gear member 422 iscontinuously connected with the ring gear member 434 through theinterconnecting member 472. The sun gear member 432 is continuouslyconnected with the ring gear member 444 through the interconnectingmember 474.

The clutch 450 selectively connects the ring gear member 434 with theinput shaft 17. The clutch 452 selectively connects the ring gear member424 with the input shaft 17. The clutch 454 selectively connects the sungear member 442 with the input shaft 17. The clutch 456 selectivelyconnects the planet carrier assembly member 436 with the sun gear member442. The clutch 457 selectively connects the planet carrier assemblymember 446 with the sun gear member 442. The brake 458 selectivelyconnects the ring gear member 424 with the transmission housing 460. Thebrake 459 selectively connects the planet carrier assembly member 446with the transmission housing 460.

The truth table shown in FIG. 5 b describes the engagement combinationand sequence of the torque-transmitting mechanisms 450, 452, 454, 456,457, 458 and 459 that are employed to provide the forward and reversedrive ratios.

Also given in the truth table of FIG. 5 b is a set of numerical valuesthat are attainable with the present invention utilizing the ringgear/sun gear tooth ratios shown. The N_(R1)/N_(S1) value is the toothratio of the planetary gear set 420; the N_(R2)/N_(S2) value is thetooth ratio of the planetary gear set 430; and the N_(R3)/N_(S3) valueis the tooth ratio of the planetary gear set 440.

FIG. 5 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is2.17.

A powertrain 510, shown in FIG. 6 a, includes an engine 12, a planetarygear transmission 514 and the final drive mechanism 16. The planetarytransmission 514 includes the input shaft 17, a planetary geararrangement 518 and the output shaft 19. The planetary gear arrangement518 includes three planetary gear sets 520, 530 and 540.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly 526. The planet carrierassembly 526 includes a plurality of pinion gears 527 rotatably mountedon a carrier member 529 and disposed in meshing relationship with boththe sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of pinion gears 537 rotatablymounted on a carrier member 539 and disposed in meshing relationshipwith both the sun gear member 532 and the ring gear member 534.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear arrangement 518 also includes seventorque-transmitting mechanisms 550, 552, 554, 556, 557, 558 and 559. Thetorque-transmitting mechanisms 550, 552, 554, 556 and 557 are rotatingtype torque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 558 and 559 are stationary-type torquetransmitting mechanisms, commonly termed brakes or reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 526. The ring gear member 524 is continuouslyconnected with the sun gear member 532 through the interconnectingmember 570. The planet carrier assembly member 526 is continuouslyconnected with the planet carrier assembly member 536 through theinterconnecting member 572. The ring gear member 534 is continuouslyconnected with the ring gear member 544 through the interconnectingmember 574.

The clutch 550 selectively connects the sun gear member 542 with theinput shaft 17. The clutch 552 selectively connects the planet carrierassembly member 546 with the input shaft 17. The clutch 554 selectivelyconnects the sun gear member 532 with the planet carrier assembly member546. The clutch 556 selectively connects the sun gear member 522 withthe planet carrier assembly member 546. The clutch 557 selectivelyconnects the sun gear member 522 with the sun gear member 542. The brake558 selectively connects the ring gear member 524 with the transmissionhousing 560. The brake 559 selectively connects the sun gear member 542with the transmission housing 560.

The truth table shown in FIG. 6 b describes the engagement sequence andcombination of the torque-transmitting mechanisms to provide the reversespeed ratio and eight forward speed ratios. The chart of FIG. 6 bdescribes the ratio steps between adjacent forward speed ratios and theratio step between the reverse and first forward speed ratio.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6 b. TheN_(R1)/N_(S1) value is the tooth ratio of the planetary gear set 520;the N_(R2)/N_(S2) value is the tooth ratio of the planetary gear set530; and the N_(R3)/N_(S3) value is the tooth ratio of the planetarygear set 540.

A powertrain 610, shown in FIG. 7 a, has the engine 12, a planetarytransmission 614 and the final drive mechanism 16. The planetarytransmission 614 includes the input shaft 17, a planetary geararrangement 618 and the output shaft 19. The planetary gear arrangement618 includes three planetary gear sets 620, 630 and 640.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly 626. The planet carrierassembly 626 includes a plurality of pinion gears 627 rotatably mountedon a carrier member 629 and disposed in meshing relationship with boththe sun gear member 622 and the ring gear member 624.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of pinion gears 647 rotatablymounted on a carrier member 649 and disposed in meshing relationshipwith both the sun gear member 642 and the ring gear member 644.

The planetary gear arrangement 618 also includes seventorque-transmitting mechanisms 650, 652, 654, 656, 657, 658 and 659. Thetorque-transmitting mechanisms 650, 652, 654 and 656 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 657, 658 and 659 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 646. The sun gear member 622 is continuouslyconnected with the sun gear member 632 through the interconnectingmember 670. The planet carrier assembly member 626 is continuouslyconnected with the ring gear member 634 through the interconnectingmember 672. The planet carrier assembly member 636 is continuouslyconnected with the ring gear member 644 through the interconnectingmember 674.

The clutch 650 selectively connects the planet carrier assembly member626 with the input shaft 17. The clutch 652 selectively connects the sungear member 642 with the input shaft 17. The clutch 654 selectivelyconnects the ring gear member 624 with the sun gear member 642. Theclutch 656 selectively connects the ring gear member 624 with the planetcarrier assembly member 646. The brake 657 selectively connects theplanet carrier assembly member 626 with the transmission housing 660.The brake 658 selectively connects the sun gear member 622 with thetransmission housing 660. The brake 659 selectively connects the sungear member 642 with the transmission housing 660.

The truth table shown in FIG. 7 b describes the combination oftorque-transmitting mechanism engagements that will provide the reversedrive ratio and eight forward speed ratios (including the extra fifthand eighth speed ratios: 5′ and 8′), as well as the sequence of theseengagements and interchanges. The torque-transmitting mechanisms 652 and657 can be engaged through the neutral condition, thereby simplifyingthe forward/reverse interchange.

The ratio values given are by way of example and are establishedutilizing the ring gear/sun gear tooth ratios given in FIG. 7 b. Forexample, the N_(R1)/N_(S1) value is the tooth ratio of the planetarygear set 620; the N_(R2)/N_(S2) value is the tooth ratio of theplanetary gear set 630; and the N_(R3)/N_(S3) value is the tooth ratioof the planetary gear set 640. The ratio steps between adjacent forwardratios and the reverse to first ratio are also given in FIG. 7 b.

A powertrain 710, shown in FIG. 8 a, has the conventional engine 12, aplanetary transmission 714, and the conventional final drive mechanism16. The engine 12 is drivingly connected with the planetary transmission714 through the input shaft 17. The planetary transmission 714 isdrivingly connected with the final drive mechanism 16 through the outputshaft 19. The planetary transmission 714 includes a planetary geararrangement 718 that has a first planetary gear set 720, a secondplanetary gear set 730, and a third planetary gear set 740.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly 726. The planet carrierassembly 726 includes a plurality of pinion gears 727 rotatably mountedon a carrier member 729. The pinion gears 727 are disposed in meshingrelationship with the sun gear member 722 and the ring gear member 724.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear arrangement 718 also includes seventorque-transmitting mechanisms 750, 752, 754, 756, 757, 758 and 759. Thetorque-transmitting mechanisms 750, 752, 754 and 756 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 757, 758 and 759 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 726. The planet carrier assembly member 726 iscontinuously connected with the planet carrier assembly member 736through the interconnecting member 770. The sun gear member 722 iscontinuously connected with the ring gear member 734 through theinterconnecting member 772. The sun gear member 732 is continuouslyconnected with the ring gear member 744 through the interconnectingmember 774.

The clutch 750 selectively connects the ring gear member 724 with theinput shaft 17. The clutch 752 selectively connects the planet carrierassembly member 746 with the input shaft 17. The clutch 754 selectivelyconnects the sun gear member 742 with the input shaft 17. The clutch 756selectively connects the ring gear member 734 with the sun gear member742. The brake 757 selectively connects the ring gear member 724 withthe transmission housing 760. The brake 758 selectively connects thering gear member 744 with the transmission housing 760. The brake 759selectively connects the planet carrier assembly member 746 with thetransmission housing 760.

The truth table of FIG. 8 b defines the torque-transmitting mechanismengagement sequence utilized for each of the forward and reverse speedratios. Also given in the truth table is a set of numerical values thatare attainable with the present invention utilizing the ring gear/sungear tooth ratios given in FIG. 8 b. The N_(R1)/N_(S1) value is thetooth ratio of the planetary gear set 720; the N_(R2)/N_(S2) value isthe tooth ratio of the planetary gear set 730; and the N_(R3)/N_(S3)value is the tooth ratio of the planetary gear set 740.

FIG. 8 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is2.17.

A powertrain 810, shown in FIG. 9 a, has the conventional engine 12, aplanetary transmission 814, and the final drive mechanism 16. The engine12 is drivingly connected with the planetary transmission 814 throughthe input shaft 17. The planetary transmission 814 is drivinglyconnected with the final drive mechanism 16 through the output shaft 19.The planetary transmission 814 includes a planetary gear arrangement 818that has a first planetary gear set 820, a second planetary gear set830, and a third planetary gear set 840.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly 826. The planet carrierassembly 826 includes a plurality of pinion gears 827 rotatably mountedon a carrier member 829 and disposed in meshing relationship with thesun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of pinion gears 837 rotatablymounted on a carrier member 839 and disposed in meshing relationshipwith both the sun gear member 832 and the ring gear member 834.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847, 848rotatably mounted on a carrier member 849 and disposed in meshingrelationship with the ring gear member 844 and the sun gear member 842,respectively.

The planetary gear arrangement 818 also includes seventorque-transmitting mechanisms 850, 852, 854, 856, 857, 858 and 859. Thetorque-transmitting mechanisms 850, 852, 854 and 856 are rotating typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 857, 858 and 859 are stationary-typetorque transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 826. The planet carrier assembly member 826 iscontinuously connected with the planet carrier assembly member 836through the interconnecting member 870. The sun gear member 822 iscontinuously connected with the ring gear member 834 through theinterconnecting member 872. The sun gear member 832 is continuouslyconnected with the planet carrier assembly member 846 through theinterconnecting member 874.

The clutch 850 selectively connects the ring gear member 824 with theinput shaft 17. The clutch 852 selectively connects the ring gear member844 with the input shaft 17. The clutch 854 selectively connects the sungear member 842 with the input shaft 17. The clutch 856 selectivelyconnects the ring gear member 834 with the sun gear member 842. Thebrake 857 selectively connects the ring gear member 824 with thetransmission housing 860. The brake 858 selectively connects the planetcarrier assembly member 846 with the transmission housing 860. The brake859 selectively connects the ring gear member 844 with the transmissionhousing 860.

The truth table shown in FIG. 9 b defines the torque-transmittingmechanism engagement sequence that provides the two reverse speed ratiosand eight forward speed ratios (as well as an extra eighth ratio: 8′)shown in the truth table and available with the planetary geararrangement 818. A sample of numerical values for the individual ratiosis also given in the truth table of FIG. 9 b. These numerical valueshave been calculated using the ring gear/sun gear tooth ratios alsogiven by way of example in FIG. 9 b. The N_(R1)/N_(S1) value is thetooth ratio of the planetary gear set 820; the N_(R2)/N_(S2) value isthe tooth ratio of the planetary gear set 830; and the N_(R3)/N_(S3)value is the tooth ratio of the planetary gear set 840. FIG. 9 b alsodescribes the ratio steps between adjacent forward ratios and betweenthe reverse and first forward ratio.

The powertrain 910, shown in FIG. 10 a, includes the conventional engine12, a planetary transmission 914, and the conventional final drivemechanism 16. The engine 12 is drivingly connected with the planetarytransmission 914 through the input shaft 17. The planetary transmission914 is drivingly connected with the final drive mechanism 16 through theoutput shaft 19. The planetary transmission 914 includes a planetarygear arrangement 918 that has a first planetary gear set 920, a secondplanetary gear set 930, and a third planetary gear set 940.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly 926. The planet carrierassembly 926 includes a plurality of pinion gears 927 that are rotatablymounted on a carrier member 929 and disposed in meshing relationshipwith the sun gear member 922 and the ring gear member 924, respectively.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937, 938rotatably mounted on a carrier member 939 and disposed in meshingrelationship with the ring gear member 934 and the sun gear member 932,respectively.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear arrangement 918 also includes seventorque-transmitting mechanisms 950, 952, 954, 956, 957, 958 and 959. Thetorque-transmitting mechanisms 950, 952, 954 and 956 are rotating-typetorque-transmitting mechanisms, commonly termed clutches. Thetorque-transmitting mechanisms 957, 958 and 959 are stationary-typetorque-transmitting mechanisms, commonly termed brakes or reactionclutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 926. The planet carrier assembly member 926 iscontinuously connected with the ring gear member 934 through theinterconnecting member 970. The sun gear member 922 is continuouslyconnected with the planet carrier assembly member 936 through theinterconnecting member 972. The sun gear member 932 is continuouslyconnected with the ring gear member 944 through the interconnectingmember 974.

The clutch 950 selectively connects the ring gear member 924 with theinput shaft 17. The clutch 952 selectively connects the sun gear member942 with the input shaft 17. The clutch 954 selectively connects theplanet carrier assembly member 936 with the planet carrier assemblymember 946. The clutch 956 selectively connects the planet carrierassembly member 936 with the sun gear member 942. The brake 957selectively connects the ring gear member 924 with the transmissionhousing 960. The brake 958 selectively connects the ring gear member 944with the transmission housing 960. The brake 959 selectively connectsthe planet carrier assembly member 946 with the transmission housing960.

The truth table of FIG. 10 b describes the torque-transmitting mechanismengagement sequence utilized to provide the reverse speed ratio and nineforward speed ratios, as well as extra second, fifth and ninth forwardspeed ratios. The truth table also provides a set of examples for theratios for each of the reverse and forward speed ratios. These numericalvalues have been determined utilizing the ring gear/sun gear toothratios given in FIG. 10 b. The N_(R1)/N_(S1) value is the tooth ratio ofthe planetary gear set 920; the N_(R2)/N_(S2) value is the tooth ratioof the planetary gear set 930; and the N_(R3)/N_(S3) value is the toothratio of the planetary gear set 940.

A powertrain 1010, shown in FIG. 11 a, includes the conventional engine12, a planetary transmission 1014, and the conventional final drivemechanism 16. The engine is drivingly connected with the planetarytransmission 1014 through the input shaft 17. The planetary transmission1014 is drivingly connected with the final drive mechanism 16 throughthe output shaft 19. The planetary transmission 1014 includes aplanetary gear arrangement 1018 that has a first planetary gear set1020, a second planetary gear set 1030, and a third planetary gear set1040.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly 1026. The planet carrierassembly 1026 includes a plurality of pinion gears 1027 rotatablymounted on a carrier member 1029 and disposed in meshing relationshipwith both the sun gear member 1022 and the ring gear member 1024.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037,1038 rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with the ring gear member 1034 and the sun gear member1032, respectively.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the sun gear member 1042 and the ring gear member1044.

The planetary gear arrangement 1018 also includes seventorque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057, 1058 and1059. The torque-transmitting mechanisms 1050, 1052, 1054 and 1056 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanisms 1057, 1058 and 1059 arestationary-type torque-transmitting mechanisms, commonly termed brakesor reaction clutches.

The input shaft 17 is not continuously connected with any planetary gearmember. The output shaft 19 is continuously connected with the planetcarrier assembly member 1046. The sun gear member 1022 is continuouslyconnected with the sun gear member 1032 through the interconnectingmember 1070. The planet carrier assembly member 1026 is continuouslyconnected with the planet carrier assembly member 1036 through theinterconnecting member 1072. The ring gear member 1034 is continuouslyconnected with the ring gear member 1044 through the interconnectingmember 1074.

The clutch 1050 selectively connects the planet carrier assembly member1026 with the input shaft 17. The clutch 1052 selectively connects thesun gear member 1042 with the input shaft 17. The clutch 1054selectively connects the ring gear member 1024 with the sun gear member1042. The clutch 1056 selectively connects the ring gear member 1024with the planet carrier assembly member 1046. The brake 1057 selectivelyconnects the planet carrier assembly member 1026 with the transmissionhousing 1060. The brake 1058 selectively connects the sun gear member1022 with the transmission housing 1060. The brake 1059 selectivelyconnects the sun gear member 1042 with the transmission housing 1060.

The truth table shown in FIG. 11 b describes the engagement combinationsand the engagement sequence necessary to provide the reverse drive ratioand the eight forward speed ratios, as well as extra fifth and eighthspeed ratios. A sample of the numerical values for the ratios is alsoprovided in the truth table of FIG. 11 b. These values are determinedutilizing the ring gear/sun gear tooth ratios also given in FIG. 11 b.The N_(R1)/N_(S1) value is the tooth ratio for the planetary gear set1020; the N_(R2)/N_(S2) value is the tooth ratio for the planetary gearset 1030; and the N_(R3)/N_(S3) value is the tooth ratio for theplanetary gear set 1040. Also given in FIG. 11 b is a chart describingthe step ratios between the adjacent forward speed ratios and thereverse to first forward speed ratio.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second and third planetary gear sets each having first,second and third members; said output shaft being continuouslyinterconnected with a member of said planetary gear sets, and said inputshaft not being continuously interconnected with any member of saidplanetary gear sets; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set; a secondinterconnecting member continuously interconnecting said second memberof said first planetary gear set with said second member of said secondplanetary gear set; a third interconnecting member continuouslyinterconnecting said third member of said second planetary gear set withsaid first member of said third planetary gear set; a firsttorque-transmitting mechanism selectively interconnecting a member ofsaid third planetary gear set with said input shaft; a secondtorque-transmitting mechanism selectively interconnecting a member ofsaid first, second or third planetary gear set with said input shaft; athird torque-transmitting mechanism selectively interconnecting a memberof said first or third planetary gear set with said input shaft or withanother member of said first or third planetary gear set; a fourthtorque-transmitting mechanism selectively interconnecting a member ofsaid first or third planetary gear set with another member of saidfirst, second or third planetary gear set; a fifth torque-transmittingmechanism selectively interconnecting a member of said first or thirdplanetary gear set with a stationary member; a sixth torque-transmittingmechanism selectively interconnecting a member of said second or thirdplanetary gear set with said stationary member; a seventhtorque-transmitting mechanism selectively interconnecting a member ofsaid second or third planetary gear set with another member of saidfirst, second or third planetary gear set, or with said stationarymember; said torque-transmitting mechanisms being engaged incombinations of three to establish at least eight forward speed ratiosand at least one reverse speed ratio between said input shaft and saidoutput shaft.
 2. The transmission defined in claim 1, wherein saidfirst, second, third, fourth and seventh torque-transmitting mechanismscomprise clutches, and said fifth and sixth torque-transmittingmechanisms comprise brakes.
 3. The transmission defined in claim 1,wherein said first, second, third and fourth torque-transmittingmechanisms comprise clutches and said fifth, sixth and seventhtorque-transmitting mechanisms comprise brakes.
 4. The transmissiondefined in claim 1, wherein planet carrier assembly members of each ofsaid planetary gear sets are single-pinion carriers.
 5. The transmissiondefined in claim 1, wherein at least one planet carrier assembly memberof said planetary gear sets is a double-pinion carrier.
 6. A multi-speedtransmission comprising: an input shaft; an output shaft; a planetarygear arrangement having first, second and third planetary gear sets,each planetary gear set having first, second and third members; saidoutput shaft being continuously interconnected with a member of saidplanetary gear sets, and said input shaft not being continuouslyinterconnected with any member of said planetary gear sets; a firstinterconnecting member continuously interconnecting said first member ofsaid first planetary gear set with said first member of said secondplanetary gear set; a second interconnecting member continuouslyinterconnecting said second member of said first planetary gear set withsaid second member of said second planetary gear set; a thirdinterconnecting member continuously interconnecting said third member ofsaid second planetary gear set with said first member of said thirdplanetary gear set; and seven torque-transmitting mechanisms forselectively interconnecting said members of said planetary gear setswith said input shaft, with a stationary member or with other members ofsaid planetary gear sets, said seven torque-transmitting mechanismsbeing engaged in combinations of three to establish at least eightforward speed ratios and at least one reverse speed ratio between saidinput shaft and said output shaft.
 7. The transmission defined in claim6, wherein a first of said seven torque-transmitting mechanisms isoperable for selectively interconnecting a member of said thirdplanetary gear set with said input shaft.
 8. The transmission defined inclaim 6, wherein a second of said seven torque-transmitting mechanismsis operable for selectively interconnecting a member of said first,second or third planetary gear set with said input shaft.
 9. Thetransmission defined in claim 6, wherein a third of said seventorque-transmitting mechanisms is selectively operable forinterconnecting a member of said first or third planetary gear set withsaid input shaft or with another member of said first or third planetarygear set.
 10. The transmission defined in claim 6, wherein a fourth ofsaid seven torque-transmitting mechanisms is selectively operable forinterconnecting a member of said first or third planetary gear set withanother member of said first, second or third planetary gear set. 11.The transmission defined in claim 6, wherein a fifth of said seventorque-transmitting mechanisms is selectively operable forinterconnecting a member of said first or third planetary gear set withsaid stationary member.
 12. The transmission defined in claim 6, whereina sixth of said seven torque-transmitting mechanisms selectivelyinterconnects a member of said second or third planetary gear set withsaid stationary member.
 13. The transmission defined in claim 6, whereina seventh of said seven torque-transmitting mechanisms selectivelyinterconnects a member of said second or third planetary gear set withanother member of said first, second or third planetary gear set, orwith said stationary member.
 14. The transmission defined in claim 6,wherein planet carrier assembly members of each of said planetary gearsets are single-pinion carriers.
 15. The transmission defined in claim6, wherein at least one planet carrier assembly member of said planetarygear sets is a double-pinion carrier.